Wireless networks have become increasingly popular, as computers and other devices can be coupled for data communications without requiring wired connections between the network nodes. One set of standards for wireless networks is the IEEE 802.11 standards, but other wireless standards or protocols might be used instead.
In the IEEE 802.11 standards, there are at least two widely-used standards, 802.11a and 802.11b, and communication systems and devices might be required to support both standards and/or be required to operate in areas where both are being used. Enhancements to the 802.11 standards have been in place, such as the 802.11g standard that allows for OFDM transmissions (802.11a is an OFDM transmission protocol) in the 2.4 GHz band.
The 802.11a protocol supports OFDM transmissions in the 5 GHz band for data rates of 6 to 54 million bits per second (“Mbps”). The 802.11b protocol supports DSSS transmissions in the 2.4 GHz band for data rates of 1, 2, 5.5 and 11 Mbps. The 802.11g protocol mixes OFDM and DSSS protocols in the 2.4 GHz band for data rates of 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36, 48 and 54 Mbps. Data transmissions are well known for these protocols, so they need not be set forth herein. They are described, for example, in ANSI/IEEE Std 802.11, 1999 Edition; IEEE Std 802.11b, 1999; IEEE Std 802.11a, 1999/Amd 1:2000(E). Those references are incorporated by reference herein for all purposes.
The 802.11b protocol can be supported by a station with a lower power than the full data rate range of the 802.11g protocol. One reason for this is that the 1 to 11 Mbps transmissions can be received at a lower signal-to-noise ratio (SNR) than the 12 to 54 Mbps transmissions. Another reason is that demodulation is simpler to implement for DSSS than for OFDM. Where power limitations exist at a station, 802.11b might be used instead of 802.11g. Where stations are not power-limited and higher data rates are needed, the 802.11g protocol might be preferred, as data rates can be as high as 54 Mbps. Additional rate extensions might be proposed and adopted as standard, but it is likely that the power-data rate trade-off will continue to exist, e.g., the trade-off between using more power to get a higher data rate or being limited to a lower rate to stay within a power budget of one or more stations in a wireless network.
It would be desirable to overcome the shortcomings of the prior art described above.